Various spectroscopic techniques have been and continue to be demonstrated for trace gas detection using a wide variety of light sources. Two absorbance spectroscopy techniques available for such measurements are direct absorbance spectroscopy and modulation spectroscopy. Though somewhat different in principle, these two techniques both can be used to measure important parameters such as temperature, pressure, gas velocity and species concentration in practical environments. However, each of these techniques includes limitations that can render it less desirable for providing optimal measurement accuracy and/or precision over a wide dynamic range.